What they don't do is give you a global linear ordering. But you don't need that in a key-value store, and you don't need that in most distributed computing.
People keep reaching for PAXOS and RAFT when they don't need it. It's pretty rare that you need a distributed linearization.
But, if CRTDs allow independent operation, don't they check the high availability box?
If node A sees deposit,withdraw and node B sees withdraw,deposit one of those is business-as-usual, the other is overdraft. You can't have a "high availability" system where some parts of the system are acting like it's okay, and other parts aren't.
Not everything is a bank, but a lot of things are often more-like-a-bank than they first appear...
However, it's distributed consensus that solves for strict serializability (I should say, not strict consistency) and high availability as a combination.
See also the Jepsen page on consistency levels.
You don't need PAXOS, RAFT, or CURP to implement a key-value store. Those are distributed state machines, all you need is distributed state.
That means you don't need a leader election. You don't need a leader. You don't need any round trips. You don't need coordination.
PAXOS was the only game in town for many decades, but there are better ways to do this now.